title: The SecB chaperone is involved in the secretion of the Serratia marcescens HasA protein through an ABC transporter.
abstract: The secretion pathways of the heme-binding protein HasA from Serratia marcescens and of the metalloproteases A, B, C and G from Erwinia chrysanthemi have been reconstituted in Escherichia coli. They are secreted in a single step from the cytoplasm across both membranes of the Gram-negative envelope, after recognition of their specific C-terminal secretion signal by their cognate ABC transporter. We report strong evidence that both HasA and the metalloproteases bind the SecB chaperone involved in the export of several envelope proteins via the Sec pathway. We also show that the secretion of the HasA protein is strongly dependent upon SecB in the reconstituted system, whereas that of the proteases is not. HasA secretion in the original host is strongly inhibited by a protein known to interfere with E.coli SecB function. We propose that the proteins secreted by the ABC pathway may have to be unfolded for efficient secretion.
authors.affiliation: Unité de Physiologie Cellulaire, Institut Pasteur (Centre National de la Recherche Scientifique, Unité de Recherche Associée 1300), Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Delepelaire
authors.forename: C
authors.initials: C
authors.lastname: Wandersman
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000502:physiology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D011232:Chemical Precipitation; D017364:Collagenases / Q000235:genetics; D010450:Endopeptidases / Q000096:biosynthesis / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005982:Glutathione Transferase / Q000235:genetics; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism / Q000502:physiology*; D009004:Monosaccharide Transport Proteins; D019897:Periplasm / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D011485:Protein Binding; D011498:Protein Precursors / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000494:pharmacology; D012706:Serratia marcescens / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C093956:HasA protein, Serratia marcescens; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; D009004:Monosaccharide Transport Proteins; D011480:Protease Inhibitors; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; C057842:SecB protein, Bacteria; C461599:maltose transport system, E coli; D005982:Glutathione Transferase; D010450:Endopeptidases; D017364:Collagenases; C074887:prtC protein, bacteria; C099750:PrtB protein, bacteria